Search PubMed⌕ Search
Home/Archive/PubMed

PubMed · 7851297

[Decrease of the lead burden of cattle within the last 20 years].

H J Hapke
View original source ↗Export metadata ↓

Abstract

After introduction of many measures in technical and hygienic fields, emission of lead was remarkably reduced within the last years. Whether these measures were followed by a real decrease of the actual lead burden of man and animals may be recognized by controlling the lead content of food. Further it was possible to quantify a biological effect as an indicator of lead burden by the activity of delta-aminolevulinic acid dehydratase in red blood cells of cows in the Hannover area and to compare actual results with those obtained twenty years ago in the same region using identical methods. Results show a remarkable decrease of lead-caused inhibition of that enzyme.

Explore related subjects

Aminolevulinic AcidAnimalsCattleEnvironmental ExposureErythrocytesGermanyLeadEnglish AbstractJournal Article

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

H J Hapke. 1994. [Decrease of the lead burden of cattle within the last 20 years].. https://pubmed.ncbi.nlm.nih.gov/7851297/

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2002

ALA and ALA hexyl ester induction of porphyrins after their systemic administration to tumour bearing mice.

The use of synthetic lipophilic molecules derived from 5-aminolevulinic acid (ALA) is currently under investigation to enhance cellular ALA penetration. In this work we studied the effect of systemic administration to mice of the hexyl ester of ALA (He-ALA) on porphyrin tissue synthesis as compared to ALA. In most normal tissues as well as in tumour, He-ALA induced less porphyrin synthesis than ALA after its systemic administration either intravenous or intraperitoneal, although explant organ cultures exposed to either ALA or He-ALA revealed equally active esterases. The only tissue that accumulated higher porphyrin levels from He-ALA (seven times more than ALA) was the brain, and this correlated well with a rapid increase in ALA/He-ALA content in brain after administration of He-ALA. This may be ascribed to a differential permeability to lipophilic substances controlled by the blood-brain barrier, a feature which could be further exploited to treat brain tumours.

Aminolevulinic Acid↗
PubMed2002

Role of 5-aminolevulinic acid in the detection of urothelial premalignant lesions.

BACKGROUND: The authors evaluated the role of 5-aminolevulinic acid (5-ALA)-induced fluorescence endoscopy (AFE) in the detection of flat urothelial lesions in light of the suggestions made for flat neoplastic lesions within the 1999 World Health Organization (WHO) classification of urinary bladder tumors. METHODS: From 1995 to 2000, 713 patients underwent 1414 AFE procedures for the detection of transitional cell carcinoma of the bladder (TCCB). Fluorescence imaging was performed with an incoherent light source (D-light; 380-440 nm) that was filtered for efficient protoporphyrin IX excitation and with cystoscopes partially blocking reflected excitation light to enable fluorescence evaluation by a red/blue color contrast 2-3 hours after 50 mL of a 3% solution of 5-ALA was instilled into the bladder. In total, 3834 biopsy specimens (mean, 2.7 specimens per AFE procedure) were taken. RESULTS: Malignant disease was found in 1250 (32.6%) of all biopsies, with 304 biopsies (24.3%) showing carcinoma in situ (cis) and dysplasia II degrees (dys II) according to the previous diagnostic criteria of the WHO. Under prior conventional white-light endoscopy, 30.3% of specimens with dys II and 52.8% of specimens with cis had been missed. CONCLUSIONS: The current results suggest that 5-ALA may be more effective in the detection of flat urothelial lesions than the current diagnostic devices.

Aminolevulinic Acid↗
PubMed2002

Structure of porphobilinogen synthase from Pseudomonas aeruginosa in complex with 5-fluorolevulinic acid suggests a double Schiff base mechanism.

All natural tetrapyrroles, including hemes, chlorophylls and vitamin B12, share porphobilinogen (PBG) as a common precursor. Porphobilinogen synthase (PBGS) synthesizes PBG through the asymmetric condensation of two molecules of aminolevulinic acid (ALA). Crystal structures of PBGS from various sources confirm the presence of two distinct binding sites for each ALA molecule, termed A and P. We have solved the structure of the active-site variant D139N of the Mg2+-dependent PBGS from Pseudomonas aeruginosa in complex with the inhibitor 5-fluorolevulinic acid at high resolution. Uniquely, full occupancy of both substrate binding sites each by a single substrate-like molecule was observed. Both inhibitor molecules are covalently bound to two conserved, active-site lysine residues, Lys205 and Lys260, through Schiff bases. The active site now also contains a monovalent cation that may critically enhance enzymatic activity. Based on these structural data, we postulate a catalytic mechanism for P. aeruginosa PBGS initiated by a C-C bond formation between A and P-side ALA, followed by the formation of the intersubstrate Schiff base yielding the product PBG.

Aminolevulinic Acid↗